The disconnect clear time is a disconnection of the A&B wires to the PBX subscriber. It is variable in 100 m/s steps from 0 to 1 seconds. The actual parameter is P16 of DSB resource. The disconnect/clear time is used by PABX's either to enable it's equipment to release or, to inform the PABX that the exchange line has recognised that the call has come to an end. There are two Problems that have come to light with regards to the disconnect/clear times, these are:
Because of the wide variety of PABX's in the field it is very difficult to obtain exact
figures for dis/clear times. Even on the same type of PABX you can have different Software
and Firmware Packages which use different dis/clear times. However as a general rule the
disconnect/clear time is set to 800 m/s, but if difficulties occur either with Phantom calls or
NDT this time should be reduced.
Last revised: January 28, 2023